Preheat the oven to 300F and line a large baking sheet with parchment paper.
In a large clean bowl, combine the egg whites, cream of tartar and salt. Beat with clean beaters until frothy.
Slowly add the granular and powdered sweeteners until the egg whites hold stiff peaks (I find that the combo of the two helps whip the air bubbles into the egg whites without the grittiness of all granular).
Sift the cocoa powder over the egg whites and gently fold in until combined and no streaks remain. Fold in the chocolate chips.
Drop by large spoonfuls onto the prepared baking sheet. Bake 25 to 35 minutes, until the meringues feel dry to the touch but are still soft (they should not feel tacky).
Remove and let cool completely on the pan before gently peeling from the parchment.